This invention relates in general to exercise equipment. More specifically, it relates to a portable rowing machine which provides a momentum effect to simulate closely the sensation of actually rowing and also simulates the sound of actually rowing.
Presently available rowing exercise machines either have an ability to store energy between the strokes, or they do not. This ability, commonly termed the momentum effect, is valuable for a variety of reasons. Exercise devices in the form of rowing units employing a flywheel to produce the momentum effect are superior to other units because they closely simulate the feel of rowing a real boat. The momentum effect gives the sensation of accelerating an inertial mass (the flywheel) during the pulling segment of the stroke, a sensation which is similar to that of accelerating a real boat. On the recovery segment the flywheel decelerates to a certain extent but maintains a large portion of its stored energy just as a boat maintains its forward momentum. The momentum effect also serves to establish a steady rhythm which makes the use of the device more enjoyable and is a superior mode of exercise in promoting cardiovascular fitness. Here the flywheel stores energy which has been imparted over a series of strokes, so a deviation in cadence or pulling force will result in a change in energy level. Regaining that level will require a compensating change in power delivered over succeeding strokes, immediately apparent as a change in the resistance offered by the unit. In this way the flywheel functions as a feedback mechanism acting to maintain a consistent rhythm and level of effort, which are desirable in cardiovascular type exercises.
In prior devices using flywheels, rotation is typically impeded by fluid or frictional resistance. Examples of devices employing fluid resistance generally employ ambient air or closed hydraulic media. These include U.S. Pat. Nos. 4,396,188; 4,249,725; and 3,266,801. Examples of devices employing frictional resistance include U.S. Pat. Nos. 4,047,715 and 247,532. These units generally employ friction elements which are held in contact with some surface of the flywheel by the action of weights, springs, setscrews or the like. In fluid resistance units the resistance is generally proportional to the speed of rotation of the flywheel. This is not true of frictional devices.
While these prior art rowing machines produce a momentum effect, they do not also produce sounds which simulate actual rowing. Further, the flywheels used in these devices are typically heavy, cumbersome or both. These qualities reflect adversely in shipping the machines, and in their cost of manufacture. The only known rowing machines which utilize actual water are large, fixed installations where one to eight rowers pull on conventional oars which reach to an open-top body of water. In large facilities of this type, there are two open-top water tanks on either side of the rowers with conduits and pumps to assist in circulating the water through the tanks. These installations are extremely expensive and not portable.
Another desired operating characteristic of rowing machines and the like is to be able to vary resistance of the machine, both before and during exercise to accomodate users having varying physical characteristics and to vary the response of the machine during an exercise. While various adjusting mechanisms are known, most require the user to stop the exercise routine for a period of time which substantially interrupts the rhythm of the exercise.
It is therefore a principal object of this invention to provide a portable rowing machine that provides a momentum effect that closely simulates actual in-water rowing and also simulates the sound of actual rowing.
Another principal object is to provide a rowing machine with the foregoing advantages that is compact and has a comparatively low weight.
Another object is to provide a rowing machine which readily allows an adjustment in the resistance of the machine without substantially interrupting the exercise.
A further object is to provide these advantages while at the same time being mechanically simple and requiring no special water seals around rotating members.